Playwright & Cypress interview questions

Auto-waiting, fixtures and isolation, network interception, tracing, and migration considerations.

3 questions in QA & Testing.

QA and TestingA 24-minute read on how the topic fits together, before the questions.QA and testing fundamentals59 short answers on one page, for revising rather than studying.

medium3

mediumScenarioCodingConcept

A Playwright test clicks a button that is visibly on screen, and roughly one run in twenty nothing happens. The button is server-rendered but the app hydrates after load. Why does the click get lost, and how do you fix the flake properly?

Playwright actionability checks pass on server-rendered markup because the element is attached, visible, stable and enabled - none of which imply React has attached its listener. The click lands on inert HTML, so this is a race with hydration, not a timing problem. Wait on a readiness signal the app exposes deliberately.

4 minmid, senior, staff

mediumConceptDesign

What does auto-waiting do in Playwright and Cypress, how do the two differ architecturally, and what can neither of them test?

Auto-waiting runs actionability checks before an action and retries assertions that are bound to a locator, so it removes timing races but never wrongness. Playwright drives the browser from a separate Node process.

6 minmid, senior

mediumConceptDesign

How do you get a browser test into the state it needs to start, without clicking through the UI to get there?

Create the data through the API, restore an authenticated session from saved cookies and storage rather than logging in each time, and stub only the third parties you do not own, so each test drives the UI solely for the behaviour it is actually asserting.

6 minmid, senior